Recently, virtualization of an open system or a server has become widely used and the system management has been complicated. Thus, in view of simplification of the system management and flexibility with rapidly-increased data amount, a storage system has commonly been introduced.
In a storage system, for example, a storage system performance tuning is executed by tuning a bandwidth throttling range of a data transfer path between a volume and a server that runs an application. Conventionally, the storage system executes tuning of the bandwidth throttling range upon receiving an instruction from an administrator.
Further, there is a conventional art that restricts storage performance based on a service level designated by a user. Further, there is a conventional art that receives designation of levels of plural items that affect the performance from a user and restricts the storage performance based on the designation.    Patent Document 1: Japanese Laid-open Patent Publication No. 2013-206229    Patent Document 2: Japanese Laid-open Patent Publication No. 2005-25422
However, when a plurality of volumes share a single transmission path, competition occurs during data transfer and achievement to a target performance becomes difficult. Thus, in order to achieve target performance, the administrator designates the volumes in which competition occurs during data transfer as monitoring the operation condition and instructs the storage system to degenerate a bandwidth throttling range of one of the volumes. Then, the storage system degenerates the bandwidth of the volume in response to the instruction from the administrator.
Here, there are plural transmission resources which can cause performance deterioration in the path from the application to the volume. As such resources, there are a redundant array of inexpensive disks (RAID) group, a processing processor, a port, and a switch port, for example. Each resource has different volumes sharing the resource. Thus, in a case of a conventional method that an administrator instructs a storage to tune a bandwidth throttling range, the administrator identifies the resources in which competition has occurred and decides a tuning method of the bandwidth throttling range of the volumes that share the identified resource. In other words, in the conventional method, the administrator's process is complicated and it is difficult to execute performance tuning of a storage system in a simple manner.
Further, in a conventional technique that restricts performance based on a designated level, since tuning is executed focusing on predetermined fixed target performance based on the designated level, setting of proper target performance is difficult and proper performance tuning of a storage system is difficult. Further, in a conventional technique in which levels of plural items are designated, setting of target values for the respective items is complicated and it is difficult to execute performance tuning of a storage system in a simple manner.